I've used a number of different methods to make panels ranging from 60mm to 1000mm. The best panels (the ones that produce the most accurate scans I made on one of my VMCs. The smaller ones I made by milling away white vinyl that was layered over 2 layers of black vinyl on glass plates. The larger ones were made from white Laminate Melamine and I milled the circles .1mm deep, then filled then with black paint. These were held by 3D printed holders for the small panels and CNC'd Aluminum holders for the larger ones. I''v tried printing patterns with a laser printer, Roland vinyl cutter and having anodized aluminum laser engraved. None were as accurate as the CNC'd parts.

Thank you for your input!
I don't own a vmc sadly but i'll buy a CNC router. Maybe i should go this route than. I want to scan really small items and therefore precision of the panels ist crucial.
Is there a list of sone sort that shows the important factors?
90° is important ofc and the distance between the dots as well. But what ist about the distance between the twp sides of the panel, their rotation and alignment?

Thank you for your input!
I don't own a vmc sadly but i'll buy a CNC router. Maybe i should go this route than. I want to scan really small items and therefore precision of the panels ist crucial.
Is there a list of sone sort that shows the important factors?
90° is important ofc and the distance between the dots as well. But what ist about the distance between the twp sides of the panel, their rotation and alignment?

Cheers

My understanding, and big bomber understands this better than I is that the most crucial parameter is the positioning of the dots and the flatness of the panels. David can compensate for the panels not being perfectly normal to each other. And it has compensation for the panels being slightly rotated retaliative to each other. That said, it is always better to not have errors that to try to compensate for them.

As for the VMC slash Router. Most CNC routers use stepper motors without encoders. Even with encoders, steppers are not anywhere near as good as servos when it comes to positional accuracy. Not to mention the difference in the mechanism for translating the rotational force of the motor to linear motion of the machine. Linear rails with preloaded ball screws will be far more precise than V rail and rack and pinion or gear reduction to timing belt drive.

However, all this is really mostly academic. You can still get good calibration results with less than laboratory grade calibration panels. It will take a little bit of work to tweak it till you get it where you get acceptable results. Read some of the threads on the forum about RMS error and calibration to understand better what you are shooting for.